1 /*
2  * STMicroelectronics Key Scanning driver
3  *
4  * Copyright (c) 2014 STMicroelectonics Ltd.
5  * Author: Stuart Menefy <stuart.menefy@st.com>
6  *
7  * Based on sh_keysc.c, copyright 2008 Magnus Damm
8  *
9  * This program is free software; you can redistribute it and/or modify
10  * it under the terms of the GNU General Public License version 2 as
11  * published by the Free Software Foundation.
12  */
13 
14 #include <linux/module.h>
15 #include <linux/interrupt.h>
16 #include <linux/platform_device.h>
17 #include <linux/clk.h>
18 #include <linux/io.h>
19 #include <linux/input/matrix_keypad.h>
20 
21 #define ST_KEYSCAN_MAXKEYS 16
22 
23 #define KEYSCAN_CONFIG_OFF		0x0
24 #define KEYSCAN_CONFIG_ENABLE		0x1
25 #define KEYSCAN_DEBOUNCE_TIME_OFF	0x4
26 #define KEYSCAN_MATRIX_STATE_OFF	0x8
27 #define KEYSCAN_MATRIX_DIM_OFF		0xc
28 #define KEYSCAN_MATRIX_DIM_X_SHIFT	0x0
29 #define KEYSCAN_MATRIX_DIM_Y_SHIFT	0x2
30 
31 struct st_keyscan {
32 	void __iomem *base;
33 	int irq;
34 	struct clk *clk;
35 	struct input_dev *input_dev;
36 	unsigned long last_state;
37 	unsigned int n_rows;
38 	unsigned int n_cols;
39 	unsigned int debounce_us;
40 };
41 
42 static irqreturn_t keyscan_isr(int irq, void *dev_id)
43 {
44 	struct st_keyscan *keypad = dev_id;
45 	unsigned short *keycode = keypad->input_dev->keycode;
46 	unsigned long state, change;
47 	int bit_nr;
48 
49 	state = readl(keypad->base + KEYSCAN_MATRIX_STATE_OFF) & 0xffff;
50 	change = keypad->last_state ^ state;
51 	keypad->last_state = state;
52 
53 	for_each_set_bit(bit_nr, &change, BITS_PER_LONG)
54 		input_report_key(keypad->input_dev,
55 				 keycode[bit_nr], state & BIT(bit_nr));
56 
57 	input_sync(keypad->input_dev);
58 
59 	return IRQ_HANDLED;
60 }
61 
62 static int keyscan_start(struct st_keyscan *keypad)
63 {
64 	int error;
65 
66 	error = clk_enable(keypad->clk);
67 	if (error)
68 		return error;
69 
70 	writel(keypad->debounce_us * (clk_get_rate(keypad->clk) / 1000000),
71 	       keypad->base + KEYSCAN_DEBOUNCE_TIME_OFF);
72 
73 	writel(((keypad->n_cols - 1) << KEYSCAN_MATRIX_DIM_X_SHIFT) |
74 	       ((keypad->n_rows - 1) << KEYSCAN_MATRIX_DIM_Y_SHIFT),
75 	       keypad->base + KEYSCAN_MATRIX_DIM_OFF);
76 
77 	writel(KEYSCAN_CONFIG_ENABLE, keypad->base + KEYSCAN_CONFIG_OFF);
78 
79 	return 0;
80 }
81 
82 static void keyscan_stop(struct st_keyscan *keypad)
83 {
84 	writel(0, keypad->base + KEYSCAN_CONFIG_OFF);
85 
86 	clk_disable(keypad->clk);
87 }
88 
89 static int keyscan_open(struct input_dev *dev)
90 {
91 	struct st_keyscan *keypad = input_get_drvdata(dev);
92 
93 	return keyscan_start(keypad);
94 }
95 
96 static void keyscan_close(struct input_dev *dev)
97 {
98 	struct st_keyscan *keypad = input_get_drvdata(dev);
99 
100 	keyscan_stop(keypad);
101 }
102 
103 static int keypad_matrix_key_parse_dt(struct st_keyscan *keypad_data)
104 {
105 	struct device *dev = keypad_data->input_dev->dev.parent;
106 	struct device_node *np = dev->of_node;
107 	int error;
108 
109 	error = matrix_keypad_parse_of_params(dev, &keypad_data->n_rows,
110 					      &keypad_data->n_cols);
111 	if (error) {
112 		dev_err(dev, "failed to parse keypad params\n");
113 		return error;
114 	}
115 
116 	of_property_read_u32(np, "st,debounce-us", &keypad_data->debounce_us);
117 
118 	dev_dbg(dev, "n_rows=%d n_col=%d debounce=%d\n",
119 		keypad_data->n_rows, keypad_data->n_cols,
120 		keypad_data->debounce_us);
121 
122 	return 0;
123 }
124 
125 static int keyscan_probe(struct platform_device *pdev)
126 {
127 	struct st_keyscan *keypad_data;
128 	struct input_dev *input_dev;
129 	struct resource *res;
130 	int error;
131 
132 	if (!pdev->dev.of_node) {
133 		dev_err(&pdev->dev, "no DT data present\n");
134 		return -EINVAL;
135 	}
136 
137 	keypad_data = devm_kzalloc(&pdev->dev, sizeof(*keypad_data),
138 				   GFP_KERNEL);
139 	if (!keypad_data)
140 		return -ENOMEM;
141 
142 	input_dev = devm_input_allocate_device(&pdev->dev);
143 	if (!input_dev) {
144 		dev_err(&pdev->dev, "failed to allocate the input device\n");
145 		return -ENOMEM;
146 	}
147 
148 	input_dev->name = pdev->name;
149 	input_dev->phys = "keyscan-keys/input0";
150 	input_dev->dev.parent = &pdev->dev;
151 	input_dev->open = keyscan_open;
152 	input_dev->close = keyscan_close;
153 
154 	input_dev->id.bustype = BUS_HOST;
155 
156 	error = keypad_matrix_key_parse_dt(keypad_data);
157 	if (error)
158 		return error;
159 
160 	error = matrix_keypad_build_keymap(NULL, NULL,
161 					   keypad_data->n_rows,
162 					   keypad_data->n_cols,
163 					   NULL, input_dev);
164 	if (error) {
165 		dev_err(&pdev->dev, "failed to build keymap\n");
166 		return error;
167 	}
168 
169 	input_set_drvdata(input_dev, keypad_data);
170 
171 	keypad_data->input_dev = input_dev;
172 
173 	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
174 	keypad_data->base = devm_ioremap_resource(&pdev->dev, res);
175 	if (IS_ERR(keypad_data->base))
176 		return PTR_ERR(keypad_data->base);
177 
178 	keypad_data->clk = devm_clk_get(&pdev->dev, NULL);
179 	if (IS_ERR(keypad_data->clk)) {
180 		dev_err(&pdev->dev, "cannot get clock\n");
181 		return PTR_ERR(keypad_data->clk);
182 	}
183 
184 	error = clk_enable(keypad_data->clk);
185 	if (error) {
186 		dev_err(&pdev->dev, "failed to enable clock\n");
187 		return error;
188 	}
189 
190 	keyscan_stop(keypad_data);
191 
192 	keypad_data->irq = platform_get_irq(pdev, 0);
193 	if (keypad_data->irq < 0) {
194 		dev_err(&pdev->dev, "no IRQ specified\n");
195 		return -EINVAL;
196 	}
197 
198 	error = devm_request_irq(&pdev->dev, keypad_data->irq, keyscan_isr, 0,
199 				 pdev->name, keypad_data);
200 	if (error) {
201 		dev_err(&pdev->dev, "failed to request IRQ\n");
202 		return error;
203 	}
204 
205 	error = input_register_device(input_dev);
206 	if (error) {
207 		dev_err(&pdev->dev, "failed to register input device\n");
208 		return error;
209 	}
210 
211 	platform_set_drvdata(pdev, keypad_data);
212 
213 	device_set_wakeup_capable(&pdev->dev, 1);
214 
215 	return 0;
216 }
217 
218 static int keyscan_suspend(struct device *dev)
219 {
220 	struct platform_device *pdev = to_platform_device(dev);
221 	struct st_keyscan *keypad = platform_get_drvdata(pdev);
222 	struct input_dev *input = keypad->input_dev;
223 
224 	mutex_lock(&input->mutex);
225 
226 	if (device_may_wakeup(dev))
227 		enable_irq_wake(keypad->irq);
228 	else if (input->users)
229 		keyscan_stop(keypad);
230 
231 	mutex_unlock(&input->mutex);
232 	return 0;
233 }
234 
235 static int keyscan_resume(struct device *dev)
236 {
237 	struct platform_device *pdev = to_platform_device(dev);
238 	struct st_keyscan *keypad = platform_get_drvdata(pdev);
239 	struct input_dev *input = keypad->input_dev;
240 	int retval = 0;
241 
242 	mutex_lock(&input->mutex);
243 
244 	if (device_may_wakeup(dev))
245 		disable_irq_wake(keypad->irq);
246 	else if (input->users)
247 		retval = keyscan_start(keypad);
248 
249 	mutex_unlock(&input->mutex);
250 	return retval;
251 }
252 
253 static SIMPLE_DEV_PM_OPS(keyscan_dev_pm_ops, keyscan_suspend, keyscan_resume);
254 
255 static const struct of_device_id keyscan_of_match[] = {
256 	{ .compatible = "st,sti-keyscan" },
257 	{ },
258 };
259 MODULE_DEVICE_TABLE(of, keyscan_of_match);
260 
261 static struct platform_driver keyscan_device_driver = {
262 	.probe		= keyscan_probe,
263 	.driver		= {
264 		.name	= "st-keyscan",
265 		.pm	= &keyscan_dev_pm_ops,
266 		.of_match_table = of_match_ptr(keyscan_of_match),
267 	}
268 };
269 
270 module_platform_driver(keyscan_device_driver);
271 
272 MODULE_AUTHOR("Stuart Menefy <stuart.menefy@st.com>");
273 MODULE_DESCRIPTION("STMicroelectronics keyscan device driver");
274 MODULE_LICENSE("GPL");
275